Apparatus and method of rapid production and harvesting of ice



May 27, 1952 G. POWNALL 2,598,429

APPARATUS AND METHOD OF RAPID PRODUCTION AND HARVESTING OF ICE FiledJuly 3, 1948 3 Sheets-Sheet l 33 33 INVENTOR.

GEORGE L. POWNALL BY W9 1;

Af s.

y 27, 1952 G. L. POWNALL 2,598,429

APPARATUS AND METHOD OF RAPID PRODUCTION AND HARVESTING OF ICE FiledJuly 3, 1948 3 Sheets-Sheet 2 A5 /5' 7i? 1 WW -L 52 l /6 4 5 2 lL.//7

-.-| 'l E] INVENTOR.

BY GEORGE L. POWNALL May 27, 1952 e. POWNALL APPARATUS AND METHOD OFRAPID PRODUCTION AND HARVESTING OF ICE 5 Sheets-Sheet 3 Filed July 5,1948 INVENTOR. GEORGE L. Pow/VA LL BY WNW Patented May 27, 1952 STATES ir" bi'i FFICE George lajPownall,London; Ohio appiicationfimy's, 194 s,-s ri 1;1io.-3s,9v3

'7 Claims. (01. 62-466) This invention relates to an-'apparatus--andmethod for automatic rapid production and-liarvesting of ice. I

An object of the invention is to' rapidly produce ice by mechanicalrefrigeration, in the form of elongate rods or sticks of'clearice to besheared ofi progressively by automaticmeans, for producing ice particlesinselected sizes or forms, as may be'desired; that is, the ice may besheared from the'sticks as uniformly shaped masses, or as chips notuniformly shaped.

Another object ofthe inventionis to provide a unique method ofaccomplishing-the foregoing objective, and also appropriateapparatustherefore which'is simple, compact, andeconomical in its operation, withmaintenance costs reduced to a practical minimum;

Another object is to provide'in an' apparatus of the characterreferred'to, efie'ctive and reliable means to produce cl'eartrans'parentice in stick or rod form; and to elfect'ielease of the sticks or rodsfor subsequent 'shearing ther'eof into particles of a desiredcharacter,-with' a substantial saving-of power in cyclic "operation-ofthe apparatus.

Another and broader objective --is-..to provide an improved method andmeans'ofco'oling Water or other liquid for any purpose. 1

These and other objects are attained by "the means described herein andillustratedup'on the accompanying drawings, in which:

Fig. l is aperspective viewxofr: the: machine.

Fig. 2 is a verticalsection-of the same, as viewed from therear'of'Fig..-'1.

Fig. 3 is a top plan'view. of the :"evaporator, the distributing headerbeing removed.

Fig. 4 is a fragmental cross section taken on line 4-4 of Fig. 2,showing ice'g-rowtlron the evaporator.

Fig. 5 is a broken-away-section at'the base-of the evaporator,showing-'icerpicks 2i; crosshead l9, guides 20, and cutterhead-22. r

Fig. 6 is abroken away elevational 'viewof the ice stick limiting barl6-and itsguiding and adjusting means. I

Fig. 7 is a fragmental enlarged cross-sectional view taken on line 1-1of Fig; 1.--

Fig. 8 is a fragmental cross-section -oi'a modificd 'form of volatilerefrigerant distributor, somewhat similar toi that of 'Figxfi. i

Fig. 9 is a layout. of:the 'refrigerant 'piping employed for fullautomaticoperationbfthe'machine, using a primary directrefrigerantwhichis volatile incharacter. 2

Fig. 10 is a top plan viewyp'artl-y broken-away,

2 showing the wate'r distributing header illustrated a't I'll- 42 ofFig. 2..-

. Fig. 11 is a pipingilayoutshowingthe arrangemen-t of elements"employed for full automatic operation of the machine using brineas therefrigerant, and as the thawing agent.

Fig. 12 is an electric wiring diagram for the systeinof Fig. 9.

"Fig.- 13 is an electric wiring diagram for the system of Fig.'11.

'Bri'efiy described, the apparatus comprises an "ce making machineincluding an evaporator and a freezing'compartment arranged verticallyto: produce long sticks or rods of ice, which in c'rcss section may besubstantially rectangular,

cylindrical, or 'of other desired contour. The

ice "sticks orrods, after formation during a freezing period,are'to.b'esubjected to a brief thawing and releasing thereoffroin the walls'of theshell offreezing compartment, whereby under theiorce ofgravity orotherwise, the sticks or rodsadvance endwise onto a limit bar or stop,which supports them:m'omentarily as a cutter or shearing means goesi'nto'operation for severing -frcmthe"lowerends-of the sticks or rods, apredetermined lengthof the latter.

The limit bar or step can be adjusted; either manually or by automaticmeans, -'to subject to the cutter or shear a substantial portion ofthe-length of the ice sticks, oralternatively, a lesser portion thereof,depending uponthe desire of theopera'torto'produce ice cubes of thetype-generally used'in cooling beverages, or'ice chips such as mightbe'desired for use in an ice cream freezer,

for example.

The machine is cyclic in its operation to alternately freeze, and thawslightly, the liquid undergoing treatment in the 'U-shaped ice-moldsassociated with the evaporator, in accordance comprisin'gl' beams 2,vertical angle irons 3,

and channel irons '4 spaced apart and strengthened by channel irons5.

A baseplaltefifl; secured to channel irons '5, furnishes a floor'forwater tank 6 'and'-water cir culatingpump 'l. At one end of watertank 6is a float controlled "water inlet (not shown) for maintaining aconstant height of water within the tank. The fresh water may come fromany source available.

Water pump I takes water through suction line 8 from the water tank anddischarges it through line 9 into a water distributing header l locatedon top of the apparatus. The water distributing header ill has a narrowslit opening 12 (Fig. 4) along one face, and spaced plate-like aprons H,which project outwardly from the header to coincide substantially withthe somewhat similar U form of the evaporator shell (Figs. 2 and 4). Asshown, the three side edges of the rojecting apron are slightly spacedfrom the faces thereby providing means to distribute water films againstthe faces 5| of the refrigerated surface, and to permit its flowdownward by gravity. Such water as is not frozen into a growing ice roddrops into the aforesaid water tank 6.

Adjacent to, and abutting the evaporator shell U shape face, is a hollowspace l3, one face 52 of which limits the outward growth of the ice rod.This hollow space may be constructed as an integral part of theevaporator structure or may be constructed as a separate apparatus andassembled with the evaporator.

rial, of identical plan view shape as the evaporator. An alternatehollow metal member of this form is also indicated as 540 in Fig. l andwhose purpose will be described hereinafter.

Directly under the multiple ice rod forming spaces is a cross bar 16bearing on the inner webs of the I beams 2 and raisable by means of setscrews l'l, one at each end of the bar, to adjust thelength of ice pieceor cube to be cut off of the elongated ice rod. Stationary pins 18 oneat each end of the bar provide for proper alignment of the bar which isslidable up and down on the pins. The pins are tightly fitted into thewebs of the I beams.

Means for cutting oft the elongated ice rods into cubes are provideddirectly under the evaporator and consists of a cross head 19 bearing inguides 28 within the webs of I beams 2.

Properly spaced ice picks 21 mounted in cutter head 22 are bolted tocrosshead [9.

The crosshead and cutter bar assembly is ac- 4 tuated in straight linehorizontal movement by means of cam 23 mounted on shaft 24 driventhrough a speed reducing gear 25 by motor 23 mounted on the structuralframework. The forward movement is transmitted by means of cam i yoke 29which is pivotally connected to crosshead [9.

Directly under the cutting mechanism is a wire mesh screen 21 to catchand direct away from the machine the cut ice cubes or chips to becollected in bags or baskets, are carried away by means of a conveyor,not shown. A light gauge metal splash guard 28 directs all droppin waterinto tank 6.

Thus it can be seen that water is circulated by the water pump from thewater tank to the distributing header on top of the machine where itfiows outward onto an apron which is slightly spaced from the woodeninsulating member thereby causing a film to run downwardly on thechannel-forming faces 5| of the evaporator to freeze into ice. Thisincremental growth of ice may be allowed to continue until spaces l5 area solid mass of clear elongated ice rods extending the full depth of thevertical evaporator,

and in width from the face of the evaporator shell to the stop plate Iforming one wall of the hollow partition. The action of the flowingwater causes clear ice to form in the well known manner.

If the tubular spaces 15 are permitted to fill with ice, the water thenoverflows the stop plate and continues to course down the stop plate onthe inner side of the hollow partition; therefore when the ice is beingthawed loose from the evaporator shell during the ice-releasing operation which will be further described hereinafter, the runnin waterserves to act as a thawing agent in releasing the ice rods from thehollow partition.

It should be understood that the ice need not completely fill the spaces15 before being released, as will be pointed out later.

The wooden insulating member on the top of the evaporator serves as ameans to limit or stop any upward growth of ice above the evaporator. Analternate member would be a hollow metal member 5&0 of the same planview shape as the evaporator, through which warm water could becirculated to release any part of ice rod that might adhere to themember above the evaporator. This Warm water circulation would takeplace when the machine is in its automatic ice releasing operation,furthermore arrangement for thoroughly draining the interior of thememberof water might also be provided to avoid any possibility of anywater freezing therein when the machine is in its freezing operation.

The machine described herein constitutes the evaporator, watercirculating system, cutting mechanism, and means and method ofrefrigeration and ice making in a new form which can be adapted into anexisting plant wherein other normal appurtenances of a refrigerationplant are already available, such as compressors, motors, condensers,brine tanks etc. Or the application and use of this equipment and systemmay also be made up as a complete packaged self-contained automatic icemaking plant, and is for use with either a primary refrigerant or asecondary refrigerant.

Novel means for the flow and efficient distribution of the volatilerefrigerant is provided when the evaporator is for use with a primaryrefrigerant.

In Fig. 7 it will be noted that the volatile refrigerant such asdichlorodifluoromethane or ammonia enters as a liquid through liquidline 30, through bushing 3| into a distributing header pipe 32, saidheader being closed at one end and also provided with small spacedorifices 33 of approximately /8" diameter. These orifices are spaced soas to spray the liquid refrigerant against the inner faces of theevaporator shell. That portion of the liquid which immediately flashesinto gas is readily removed, leaving the remaining liquid (approximatelyto course downward along the inner faces of the evaporator shell therebywetting that surface for efficient heat transfer. As the liquid passesdownward it also takes up heat from the evaporator wall and flashes intogas with the result that by the time the liquid has reached the bottompractically all of it has flashed into gas and has performed itsefficient service in taking up heat given off by the water being frozeninto ice on the outer face of the evaporator wall.

This novel means of refrigerant distribution is far more efiicient thanthe old method of socalled dry expansion, and is comparative in stealer;

results w t t seam fee ers asewith the distinct advantage theta lesservolume of primary refrigerant is re i-red than with the indicatedas 34and the ice formation as 35 in Fig. 7. i p

An evap-oratorshell 36, provided for freezing elongated ice rods ontwo'eppb'sed major walls of the shell is shown in Fig. aande n be usedin any number as inner sections in connection with separate hollowpartitions in building 'up a machine capable of freezing larger.tenfiags" of Or, for example, the maeniziemay ist of two of the outershellsloiie righthan'd and the other left hand) as shown iriFiQ-together with one of the double faced shells (Fig. 8) efiicientlyfastened, together tdrornji 9; machine.

One of the objects of this inventienistse provision of means and methodof manufacturing clear ice cubes automatically, andsuch a refrigerantpiping lay-out to aceoiripli'sh' these results is shown in Fig. 9. Anleetfidwirifig diagram for this purpose is shown in Fi'gll'2fas'representative. v

The core of the aUtOI'natiC operation isfthiol'igh timers TI and T2either of which can" be manipulated to regulate a freezingfopeiation anda succeeding alternate thawing (and cube cutting) operation incontinuous cycles by means of opening and closing solenoidcontrolledvalves, and starting and stopping the motor that. operates thecutting means. The compres'sorA and water pump 1 are in continuousoperation.

In addition to the'com'pr'essor A, other components of the usualrefrigeration s'ystem are indicated as, condenser B, receiver 0, andevapcrating coils D in eitheran ice storage compartment or ice storageroom. In addition, when dichlorodifiuoromethane is used as, a primaryrefrigerant a heat exchanger'or accumulator E is also used in thesuction gas line toboil' off into gas any liquid refrigerant returningthrough the suction line en-route from the evaporator to the compressor.n v r To place the machine in automatic operation .flooded operation.Refrigerant Ii'qiiid spr y is for producing cubes of ice, 2. main lineswitch 54 (Fig. 12) is used to close theelet-rical circuit, therebystarting the compressor A anda'lso water pump 7. The central push-buttonof timer 'Tl should then bedepr'essed to place the system under thecontrol of that timer. switch 64 would'then energize and epen' 'soleno'id valves SI, S2, and 83, thereby eausihg fiow of the liquidrefrigerant rom the reeiver'C' through the heat exchanger E, through athermostatic expansion valve El, into the liquid header 32 (see Fig. 9)inside the top of the'evaperator shell I, the resulting evaporatedrefrigerant'gas then passes from'the evaporat'oi shell at the bottomthrough the heat exchanger and back 'to the compressor A, where 'it' iscompressed and discharged through open solenoidvalve st into thecondenser; after liquifyin'g the liquid then passes into the receiver 0,its starting point. All other solenoid valves i'nthe: system remainclosed during this freezing operation. The flow. of the liquidrefrigerant through: the thermostatic expansion valve Eliscontrolledinamount according to needs as registered in superheat' by-abulb Bl located on the suctionline and connected to the thermo valve E-lby means of; a; capillary tube CI. The operationof this typeof valve iswell understood by those well versed in the trade.

7 Qbvi ously,- the time required'itofreezefthe. multiple ice rods willbe governed by the tem- The timed r'odfinto the 'a'daaceiit mines'e'tting it than as 'vi'cung two services. i. e;, refngerati .orator'wall. to release the, ice rods. v r v v same time'thef'fiiotorllioperating thecutting .6 pera'ture maintained in I t purpose ordesoliptifin herein wem'ay assume that it is 45 minutes, t erefore the tSwitch Tl will be set accordingly for th'e z'ingeyde; However it must bel'lilfirstdfid th'at anytime setting can be made adjustable. V v V q'the'time switch. reaehs'tne end'er this I -"651;""giZelsl the aboveindicated solenoid vanes causing their respe tive; closure, therebystepping cir cili't ofthe refrigerant the rreez ng'bperation. At the'sametime it will energizeahd open "solenoid valve s4; perrnitti-ng hotgas to I pass through thefdi'scharge lihefas indicated by the evaporatorshell thereby warming the. surface of sam to the icfods thefe 61h.

from the water 'tlieiehy'i" doTv'vTn? one race the theice r'o d 0 haerrate. v i I q Atthe'same ime, solenoid vaiv 'sfopned thereby permtuiienquia to pass th ugn'tnermositaticfeipaiisien valve E2 intoaiseconuary coil located in the iee'storag'ecab et; thereby'profltne icestorage, an also furnishing n cessary refrigerant forcompression'as hotgas to warm up the" evap- "Also at that mechanism W111 be started.rhermo tatie expansion valve E2 ukevvise hasf'af bulb sz located on thesiic'tiofi li n'e connected through capillary tube. C2 te'eentrti itsaction.

when theiee "rods are thawed tese rrem the evap-o'ratera u hollowpartition,;tney dropuown ontetar lfifwhic'h has beenadjusteqih'l'l'eight to give the proper lengtliof cube desired, The cuttingmechanism which hasa1s'o benlplitfin operationby the time switch euts'them 611" into eubes, and lip; IZI puSh'es the resultingcubes 01f er thear is ontoth'e wire mesh creen. 21.

The thawing-releasing, and cutting operation does not cohsu'nie'inuchtime, perhaps. 15 minutes, thei'for the 'tin'ie switch settin will beaccordinglyflhotvever as previously stated the setting on eitheroperation is adjustable; Consequently when thi'sflatteroperation iscompleted the time switch will again alterthe circuits and start anotherfreezing operation. i 1

During the thawing-releasing cycle of Operation the evaporator shell Ihaving been temporar'ily serving as a condenser; may'have a small amountofliq'lii'd refri erantac'eumulated' in its basewhich may run out intothefsfiftion line whenanother cycle is started by the initiationofjthefreezing operation. Accumulated liquid refrigerant istransferred/to the heat exchanger or accumulator E upon the initiationortne cycle in order to prevent possible damage to the compressor thatmight be caused by excessive liquid return. During the initial stages ofthe new freezing cycle, element E containing the liquid refrigeranttemporarily serves as a flooded type evaporator until such time asall'of the liquid refrigerant contained in' theshell" has 7 been; boiledoff into gas by the operation of the compressor thereby disposing of anysmall amounts of liquid refrigerant which originally accumulate in theevaporator during the thawing-releasingcycle.

Ordinary refrigerant hand stop valves 31 are located throughout thesystem for use'whe n repairs are being made. Likewise a hot gas line asindicated by 53 and with ordinary hand' stop valves areincluded' intherefrigerant-piping layout. for, defrosting the secondary. coils .DJmanually when necessary. Refrigerant fittings 38 with -standst l "t meshscreens therein are also included in the lay-out to protect the seats ofthe various automatic valves from scale etc.

Fig. 11 shows the refrigerant piping lay-out when the machine is forautomatic operation with brine as the refrigerant.

Cold brine is taken from brine tank 39 by means of brine pump 40 throughsuction line 4|, and discharged into the evaporator shell i at thebottom. Circulating through the evaporator where it picks up the heatgiven off by the water being frozen on the outer face of the evaporatorwall it then flows through line 42 to be dumped back into the main coldbrine tank 39, for recooling by other means not shown. Brine pump 40 isin continuous operation, both during the freezing and thawing operation.

On the above cold brine suction line 4| is solenoid controlled valve S6,and on discharge line 42 is another solenoid controlled valve S1.

This brine flow circuit is maintained throughout the freezing operationaccording to the time setting of the time switch Tl. At the end of thefreezing operation the time switch de-energizes solenoid valves S6, andS1 causing their closure, and at the same time energizes solenoidcontrol valves S8, and S9 causing them to open, and also starts thecutting mechanism motor, (see Fig. 13)

The character 43 indicates a fresh warm water tank in which fresh waterfrom any source available is maintained at constant height by means of afloat valve (not shown). The water in this tank will flow directly towater tank 6 located under the machine as needed to maintain a constantheight in tank 6. is located brine coils 44 which in connection withlines 45 and 46, brine pump 40, and evaporator I form a closed circuithereinafter known as the warm brine circuit.

When solenoid valves S8 and S9 are opened, the brine pump then receivesits brine through suction line 45 connected with coils 44, and thendischarges the brine into the evaporator. After leaving the evaporatorthe brine flows through line 46 which is also connected to coils 44.

This circuit causes the brine to pick up heat from the water in tank 43,warming itself sufficiently to thaw and release the ice rods from theouter face of evaporator shell I.

This circuit is also doing the double duty of cooling relatively warmwater in tank 43 which will be used for ice making after its passageinto tank 6. The operation of cutting the cubes and the alternatefreezing and releasing operations in cycles are the same as describedpreviously. The only structural difference in the evaporator of Fig. 11is that when a brine system is used, there is no header such as 32;within the evaporator.

With further reference to the stop bar 16 of Fig. 2, it will beunderstood that by adjusting the bar upon its guide means I8 todifferent elevations, the amount of ice to be struck from the lower endsof the ice sticks by the picks or cutters 2i, may be varied. Manualmeans in the form of adjusting screws IT is illustrated upon thedrawings for this purpose, along with suitable power means such assolenoids 18 or other motor devices adapted to automatically elevate thebar under certain operating conditions to be explained.

In the wiring diagrams of Figs. 12 and 13, the line wires are indicatedat and Bi, and the load wires 62 and 63 are seen to supply current tothe various electrical elements in a most con- Within water tank 43 fventional manner scarcely necessary to explain. The timed switch 64 ineach instance is adapted to close and open the circuits 65-E6 and 6I68,in alternation, through selected time intervals established by one orthe other of the timers TI and T2. The timers may include centralpushbuttons as shown, to be manually depressed by the operator ofthe'machine, depending upon whether the machine is to produce cube iceor chipped ice. In the previous explanation, the production of cube icewas assumed, and such production was initiated by depressing thepushbutton of timer TI, to place the system under the control of thattimer.

To produce chipped ice, the operator need only depress the push-buttonof timer T2, so a to place the switch 64 under the control of timer T2,which has a different setting than timer Tl. In other words, timer T2serves to operate the switch 64 at shorter intervals of time than timerTl. As a result of the shorter time period mentioned, the ice machinewill operate to produce incomplete or partially formed ice rods orsticks within the molds I5, and these partially formed rpds or stickswill be released onto the stop bar It in the form of ice channels ofgeneral U-shape, which are very easily disintegrated by the picks 2|.

It is desirable, when producing chipped ice, to maintain the stop bar ata higher elevation than is illustrated by Fig. 2, and this may beaccomplished automatically by energizing the solenoid coils 10 atopposite ends ofthe stop bar, for lifting the bar through the agency ofthe armatures or cores H which are attached to the bar by means ofbrackets 12. As the wiring diagrams of Figs. 12 and 13 indicate, thesolenoids are under the control of the timer T2 only, so that they areenergized only in the course of chip ice production. When the machine isoperated under the control of timer T l no energization of solenoids i0is possible, and therefore the stop bar is will remain in the loweredposition for use in producing cube ice.

It will be understood from the foregoing, that the machine can beoperated under the control of timer TI to produce cube ice, oralternatively, it can be operated under the control of timer T2toproduce chipped ice. Timer T I accordingly will be set to keep themachine in operation for a sufficient period of time to ensure theformation of solid ice sticks within the molds before initiating thethawing and releasing period. On the other hand, timer T2 will be set toprovide a more rapid cycle of freezing and thawing, which is moreeconomical and expeditious to the production of chipped ice.

In view of the foregoing explanation, it will be apparent that the sameice machine can be operated to produce ice cubes, or chipped ice, at thewill of the operator. The selection is made simply by depressing thecentral push-button 14 or 15 of the proper timer.

What is claimed is:

1. In ice making apparatus, an evaporator which comprises an enclosedhollow shell having at least one substantially vertical wall, said wallhaving vertically extending corrugations forming spaced verticalchannels of U-shaped cross-section, a plate abutting outer edges of thecorrugated wall forming a plurality of channel-shaped mold spacesbetween the plate and the corrugated wall, each mold space being open atthe top and bottom, means for introducing a refrigerant into the shellto contact the inner side of the corrugated wall, means for removing therefrigerant from the shell, and means for introducing water into theopen tops of the mold spaces to flow down the spaces and congeal as iceon the outer side of the corrugated wall.

2. Ice making apparatus in accordance with claim 1 characterized by thefact that the means for introducing refrigerant into the shell is aspray head disposed within the shell and adapted to spray volatileliquid refrigerant on the inner surface of the corrugated wall adjacentthe top thereof to flow down the corrugated wall opposite the water.

3. In ice making apparatus, an evaporator which comprises an enclosedhollow shell having at least one substantially vertical wall, said wallhaving vertically extending corrugations forming spaced verticalchannels of U-shape in section, a spray head disposed within the shelland adapted to spray volatile liquid refrigerant on the inner side ofthe corrugated wall adjacent the top thereof, the refrigerant flowingdownwardly in contact with the inner side of said corrugated wall, meansfor flowing water down the channels on the outer side of the shell tocongeal as ice thereon, and means for removing the refrigerant from theshell.

4. An ice making apparatus which comprises an evaporator having anenclosed hollow shell provided with at least one substantially verticalwall, said wall having vertically extending corrugations forming spacedelongated substantially straight vertical channels of U-shapedcrosssection, means for introducing a refrigerant into the shell anddirecting the same against the inner side of the corrugated wall, meansfor removing the refrigerant from the shell, means for flowing waterdown the channels on the outer side of said vertical wall, said waterbeing congealed, as ice thereon by said refrigerant, means for heatingthe inside of said wall while the ice is congealed thereon to releasethe ice and cause it to descend said channels, a stop member disposedbelow said channels and adapted to arrest the descent of the ice, and asharp edged ice pick mounted to reciprocate horizontally in a planespaced between said stop member and the lower end of said channels tochop the ice into small particles.

5. Ice making apparatus in accordance with claim 4 characterized by thefact that the stop member is vertically adjustable between a lower iceblock making position and an upper ice chip making position, and thatmeans are provided for holding the stop member at each of saidpositions.

6. Ice making apparatus which comprises an evaporator having an enclosedhollow shell provided with at least one substantially vertical wall,said wall having vertically extending corrugations forming spacedelongated substantially vertical substantially straight channels ofU-shaped cross-section, means for introducing a refrigerant into theshell and directing the same against the inner side of the corrugatedwall, means for removing the refrigerant from the shell, a thermallyinsulated member mounted on the top of said wall, said member having avertical face flush with and extending upwardly from the outside of saidwall, and means for directing water against said face of said member toflow down the channels on the outer side of the shell, said Water beingcongealed as ice thereon by said refrigerant.

7. Ice making apparatus which comprises an evaporator having an enclosedhollow shell provided with at least one substantially vertical wallhaving vertically extending corrugations forming spaced elongatedsubstantially straight vertical channels of U-shaped cross section,means for introducing a refrigerant into the shell and directing thesame against the inner side of the corrugated wall, means for removingthe refrigerant from the shell, a thermally insulated memher mounted onthe top of said wall, said memher having a vertical face flush with andextending upwardly from the outside of said wall, an apron member spaceda short distance from and extending downwardly toward said face of saidmember, and means for directing water onto said apron to flow down saidapron onto said face and down the channels on the outer side of thechannel, said water being congealed as ice thereon by said refrigerant.

GEORGE L. PO-WNALL.

REFERENCES CITED The following references are of record in the file ofthis patent:

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